JP7375897B2 - electrical equipment - Google Patents

Description

The present invention relates to electrical equipment that uses a battery pack to operate loads such as motors and lighting.

Electrical devices such as power tools are now powered by battery packs using secondary batteries such as lithium ion batteries, and electric devices are increasingly becoming cordless. The battery pack is configured to be detachable from the main body of the electrical device, and when the voltage drops due to discharge, the battery pack is removed from the main body of the electrical device and charged using an external charging device. Normally, the output voltage of a battery pack is fixed, but in Patent Document 1, a plurality of battery units are provided in a housing that accommodates batteries, and a connecting means is used to determine whether to output them as a series connection or a parallel connection. A power supply device for electrical equipment has been proposed that is selectable so as to be compatible with equipment with different voltages.

Japanese Patent Application Publication No. 2014-17954

For users, when using multiple electrical devices, it is cumbersome to prepare different types of battery packs for each, so it is possible to create an easy-to-use battery pack that can be used with electrical devices with different voltages by switching the voltage. desired. Furthermore, it is desired to realize an easy-to-use electrical device that does not require special operations when switching voltages and is free from the risk of operational errors.

The present invention has been made in view of the above background, and an object of the present invention is to provide a plurality of positive electrode terminal groups and a plurality of negative electrode terminal groups when a battery pack capable of switching between high voltage and low voltage output voltages is installed. An object of the present invention is to provide an electrical device that can detect abnormalities such as short circuits and poor contacts in a group of terminals in advance.
Another object of the present invention is to determine whether or not a short circuit occurs in a plurality of positive terminal groups and negative terminal groups when a battery pack capable of switching between high voltage and low voltage output voltages is installed. An object of the present invention is to provide an electrical device that establishes a series connection of cell units.
Still another object of the present invention is to provide a battery pack that can switch between high and low output voltages, and if a short circuit occurs in either the positive terminal group or the negative terminal group, An object of the present invention is to provide an electrical device in which a power path from a battery pack to the electrical device remains cut off.

Representative features of the invention disclosed in this application are as follows.
According to one feature of the present invention, there is provided an electrical equipment main body to which a battery pack can be attached, the battery pack attachment part to which the battery pack can be attached, a positive input terminal connectable to the battery pack, a negative input terminal A battery pack mounting portion having a terminal, a first shorting terminal, and a second shorting terminal, a conductive state in which the first shorting terminal and the second shorting terminal are connected to each other, and a first shorting terminal. a short circuit having a disconnection state in which the terminal and the second short circuit terminal are mutually disconnected; and the negative input terminal, the first short circuit terminal, the short circuit, the second short circuit terminal, and the positive input terminal. and a load device configured to receive power from the battery pack, and when the positive input terminal and the first shorting terminal are short-circuited, or when the negative input terminal and the second shorting terminal are short-circuited. , the short circuit is disconnected, and the power supply from the battery pack to the load device is cut off.

According to another feature of the present invention, the battery pack is attached to the battery pack mounting portion with the positive input terminal and the first shorting terminal short-circuited, or with the negative input terminal and the second shorting terminal short-circuited. When installed, the short circuit is cut off.

According to still another feature of the present invention, the battery pack mounting portion has a pair of rail grooves that extend in the mounting direction in which the battery pack is mounted and are configured to be spaced apart in the left-right direction intersecting the mounting direction, The positive input terminal, the first shorting terminal, the second shorting terminal, and the negative input terminal are arranged inside the pair of rail grooves in the left-right direction. It has a cutting part for cutting off the short circuit.

According to yet another feature of the present invention, a disconnection section is provided for disconnecting a short circuit. Moreover, it has a microcomputer that detects the respective voltages of the positive input terminal, the first short-circuit terminal, the second short-circuit terminal, and the negative input terminal, and the cutting section is configured to be turned on and off by the microcomputer. Ru. Further, the first short-circuiting terminal is configured to be connectable to the positive electrode of one of the plurality of cell units constituting the battery pack, and the second short-circuiting terminal is configured to be connectable to the positive electrode of one of the plurality of cell units constituting the battery pack. The short circuit is configured to be connectable to the negative electrode of another cell unit, and the short circuit is configured to connect the plurality of cell units in series.

According to still another feature of the present invention, an electrical device is provided that includes an electrical device main body and a battery pack that can be attached to a battery pack mounting section. The battery pack includes a plurality of cell units in which a plurality of battery cells are connected in series, a second positive terminal connected to the positive terminal of one of the plurality of cell units, and a second positive terminal connected to the negative terminal of the first cell unit. a second negative electrode terminal connected to the positive electrode of another cell unit among the plurality of cell units, a first negative electrode terminal connected to the negative electrode of another cell unit, and a plurality of cells. The unit includes a second positive terminal, a second negative terminal, a first positive terminal, and a case that accommodates the first negative terminal, and the first shorting terminal is configured to be connectable to the second positive terminal. , the second shorting terminal is configured to be connectable to the first negative terminal. Further, the short circuit is configured to connect a plurality of cell units in series.

According to the present invention, it is possible to effectively prevent a failure caused by a short circuit between a plurality of connecting terminals. Furthermore, it is possible to realize an electrical device in which the power supply path from the battery pack is not connected when a short circuit occurs between the connection terminals.

FIG. 2 is a diagram for explaining how the battery pack 100 according to the present invention is attached to the power tool main body 1, 201. FIG. 1 is a perspective view of a battery pack 100 according to an embodiment of the present invention. (A) is a partial perspective view showing the shapes of positive terminals (162 and 172) and negative terminals (167 and 177), and a diagram showing the connection circuit when outputting high voltage, and (B) is a terminal of high voltage electrical equipment. 5 is a partial perspective view showing a connection state between a portion 50 and a terminal on the battery pack 100 side. FIG. (A) is a partial perspective view showing the shapes of positive terminals (162 and 172) and negative terminals (167 and 177), and a diagram showing the connection circuit at low voltage output, and (B) is a terminal of low voltage electrical equipment. FIG. 3 is a partial perspective view showing a connection state between a portion 220 and a terminal on the battery pack 100 side. 1 is a block diagram showing a basic internal circuit of a battery pack 100. FIG. FIG. 2 is a circuit diagram of a high voltage electrical device to which an automatic voltage switching type battery pack 100 is connected. FIG. 2 is a circuit diagram of a high-voltage electrical device (power tool main body 1) according to the present embodiment. 8 is a detailed circuit diagram of the main switch 63, second switch 68, and third switch 65 in FIG. 7. FIG. It is a flowchart showing the control procedure of the microcomputer 60 when the battery pack 100 is attached to the high-voltage electric device (power tool main body 1) according to the present embodiment.

Embodiments of the present invention will be described below based on the drawings. In the following figures, the same parts are denoted by the same reference numerals, and repeated explanations will be omitted. In this specification, an electric tool operated by a battery pack will be used as an example of an electric device.

FIG. 1 is a diagram for explaining how a battery pack according to this embodiment is attached to a power tool. There are various types of power tools, which are a form of electrical equipment, and in addition to power tools that use battery packs with a rating of 18V, which are currently widely used, there are also battery packs with a rating of 36V that provide higher output. Power tools using this are commercially available. Further, the applicant has commercially available a battery pack 100 that can be attached to either the power tool main body 201 with a rating of 18V or the power tool main body 1 with a rating of 36V.

The power tool bodies 1 and 201 shown in FIG. 1 are both called impact tools. The power tool body 1, 201 is a tool that attaches a tip tool such as a bit or socket wrench (not shown) to the output shaft 10, 210, and performs tightening work by applying rotational force or impact force in the axial direction to the tip tool. . Here, a hexagonal hole (not shown) having a hexagonal cross section is formed in the output shaft 10, and a one-touch mounting mechanism 8, 208 is provided. The power tool main body 1, 201 includes a housing 2, 202, which is an outer frame forming an outer shape. The housing 2, 202 is formed with a substantially cylindrical body portion 2a, 202a and a handle portion 2b, 202b extending in a perpendicular direction (downward) from near the axial center of the body portion 2a, 202a. A trigger-like operation switch 4, 204 is provided in a part of the handle portions 2b, 202b near where the index finger of the operator touches when gripping the handle portion 2b, 202b. A forward/reverse switching lever 5, 205 for switching the rotation direction of the output shaft 10, 210 is provided near the operation switch 4, 204. Battery pack mounting parts 2c and 202c for mounting the battery pack 100 are formed below the handle parts 2b and 202b.

The power tool main body 201 is a conventional electric device using a battery pack with a rated voltage of 18V. A conventional 18V battery pack (not shown) houses only one cell unit consisting of five 3.6V rated lithium ion battery cells connected in series, or a battery pack like this. Two sets of cell units are housed and connected in parallel to each other. The power tool main body 1 is an electrical equipment main body of this embodiment that uses a battery pack with a rated voltage of 36V. Inside the 36V compatible battery pack 100, two sets of cell units each consisting of five 3.6V rated lithium ion battery cells connected in series are housed, and these two cell units are connected in series. A rated output of 36V can be obtained. Note that in this specification, a voltage of 18V is referred to as a "low voltage" in the sense that it is a lower voltage than 36V. And 36V is called "high voltage".

A conventional 18V battery pack (not shown) can be attached to the power tool main body 201. On the other hand, the battery pack 100 of the present embodiment has the terminal structure on the battery pack 100 side and the terminal structure on the terminal part 50 on the device side of the power tool main body 1, so that the power tool main body 201 can also be connected to the power tool main body 201. It can also be attached to main unit 1. When the battery pack 100 is attached to the 18V power tool body 201 as shown by arrow a1, the output of the battery pack 100 automatically becomes 18V, and when it is attached to the 36V power tool body 1 as shown by arrow a2, the output of the battery pack 100 becomes 18V. It was configured so that the output would automatically become 36V.

The power tool body 1 is an electrical equipment body with a rated voltage of 36V, and a battery pack 100 capable of outputting 36V is attached to the battery pack attachment portion 2c as shown by arrow a2. Inside the battery pack 100, two sets of cell units in which five 3.6V lithium ion battery cells are connected in series are housed, and by changing the connection method of the two sets of cell units, 18V output and 36V output can be output. You can switch between both. The battery pack 100 that is capable of outputting low and high voltages in this manner is referred to herein as a "variable voltage battery pack." In order to attach the battery pack 100 to the power tool main bodies 1 and 201 with different voltages as shown by the arrows a1 and a2, the rails and terminals of the battery pack attachment parts 2c and 202c should have approximately the same shape. , it is important to be able to switch the output voltage of the battery pack 100. At this time, it is important to ensure that the output voltage of the battery pack 100 corresponds to the rated voltage of the electrical device or power tool body to which it is attached, and to prevent voltage setting errors from occurring.

FIG. 2 is a perspective view of a battery pack 100 according to an embodiment of the present invention. The battery pack 100 can be attached to and removed from the battery pack attachment parts 2c and 202c (see FIG. 1), and can be connected to low voltage (18V here) depending on the terminal shape on the power tool main body 1 or 201 side. The high voltage (36V in this case) output is automatically switched. Further, in order to have mounting compatibility with a conventional battery pack rated for 18V, the shape of the mounting portion of the battery pack 100 is the same as that of the conventional battery pack. The housing of the battery pack 100 is formed by a lower case 101 and an upper case 110 that can be divided vertically. The upper case 110 has a mounting mechanism formed with two rails 138a and 138b for mounting on the battery pack mounting portion 2c. The rails 138a and 138b are formed to extend in a direction parallel to the mounting direction of the battery pack 100 and to protrude from the left and right side surfaces of the upper case 110. The rails 138a, 138b are formed in a shape corresponding to a rail groove (not shown) formed in the battery pack mounting portion 2c of the power tool main body 1, and the rails 138a, 138b fit into the rail groove on the electrical equipment main body side. In this state, the battery pack 100 is fixed to the power tool main body 1, 201 by being locked by the locking portion 142, which is a pawl of the latch 141. When removing the battery pack 100 from the power tool main body 1, 201, by pressing the latches 141 on both the left and right sides, the locking portions 142 move inward to release the locked state, and the battery pack is removed in that state. 100 in the opposite direction to the mounting direction.

The lower surface 111 and the upper surface 115 of the upper case 110 are formed into a stepped shape, and a plurality of slots 121 to 128 are formed extending rearward from the connecting portion thereof. The slots 121 to 128 are cut out parts having a predetermined length in the battery pack mounting direction, and inside these cut out parts, the power tool main body 1, 201 or an external charging device ( A plurality of connection terminals (described later with reference to FIG. 4) that can be fitted with device-side terminals (not shown) are provided. Among the slots 121 to 128, the slot 121 on the side closer to the right rail 138a of the battery pack 100 serves as an insertion port for a positive terminal for charging (C+ terminal), and the slot 122 serves as an insertion port for a positive terminal for discharging (+ terminal). . Furthermore, the slot 127 on the side closer to the left rail 138b serves as an insertion opening for a negative terminal (-terminal). A plurality of signal terminals for transmitting signals to the battery pack 100, the power tool body 1, 201, and an external charging device (not shown) are arranged between the positive electrode terminal and the negative electrode terminal. Four slots 123-126 are provided between the power terminal groups. The slot 123 is a spare terminal insertion opening, and no terminal is provided in this embodiment. The slot 124 is an insertion opening for a T terminal for outputting a signal serving as identification information of the battery pack 100 to the power tool body or the charging device. The slot 125 is an insertion port for a V terminal into which a control signal from an external charging device (not shown) is input. The slot 126 is an insertion opening for an LS terminal for outputting battery temperature information from a not-shown thermistor (temperature sensing element) provided in contact with the cell. A slot 128 for an LD terminal is further provided on the left side of the slot 127, which serves as an insertion opening for a negative terminal (-terminal), for outputting an abnormal stop signal from a battery protection circuit (not shown) included in the battery pack 100. .

A raised portion 132 is formed on the rear side of the upper surface 115. A recessed stopper portion 131 is formed near the center of the raised portion 132 . The stopper portion 131 becomes an abutment surface when the battery pack 100 is mounted on the battery pack mounting portions 2c, 202c. When the battery pack 100 is attached to a predetermined position on the power tool main body 1, 201, a plurality of terminals (equipment side terminals) arranged on the power tool main body 1, 201 and a plurality of connections arranged on the battery pack 100 are connected. The terminals touch and become conductive.

FIG. 3(A) is a partial perspective view showing the shapes of the positive terminals (162 and 172) and negative terminals (167 and 177) of this embodiment, and a diagram showing the connection circuit when outputting a high voltage. FIG. 3 is a partial perspective view showing a connection state between a terminal section 50 of a high-voltage electric device and a terminal on a battery pack 100 side. As shown in FIG. 3A, an upper positive electrode terminal 162 and a lower positive electrode terminal 172 are arranged side by side in the slot 122 of the battery pack 100. The upper positive electrode terminal 162 and the lower positive electrode terminal 172 are formed by pressing a metal plate, and have legs firmly fixed to the circuit board 150 by soldering or the like. The upper positive electrode terminal 162 and the lower positive electrode terminal 172 are arranged apart from each other and are electrically non-conductive. Similarly, in the slot 127, an upper negative electrode terminal 167 and a lower negative electrode terminal 177 are arranged side by side. The upper positive electrode terminal 162 and the upper negative electrode terminal 167, and the lower positive electrode terminal 172 and the lower negative electrode terminal 177 are the same metal parts.

Inside the battery pack 100, an upper cell unit (first cell unit) 146 and a lower cell unit (second cell unit) 147 each having five lithium ion battery cells connected in series are accommodated. The positive electrode of the upper cell unit 146 is connected to the upper positive electrode terminal 162, which corresponds to the first positive electrode terminal, and the negative electrode of the upper cell unit 146 is connected to the lower negative electrode terminal 177, which corresponds to the first negative electrode terminal. Similarly, the positive electrode of the lower cell unit 147 is connected to the lower positive electrode terminal 172 corresponding to the second positive electrode terminal, and the negative electrode of the lower cell unit 147 is connected to the upper negative electrode terminal 167 corresponding to the second negative electrode terminal. Ru. In this configuration of the battery pack 100, the positive input terminal on the power tool main body 1 side is connected to the upper positive electrode terminal 162, the negative input terminal is connected to the upper negative electrode terminal 167, and the lower electrode input terminal is connected to the upper negative electrode terminal 167 as shown by the dotted line 59. If the side positive electrode terminal 172 and the lower side negative electrode terminal 177 are electrically connected, the output of the series connection of the upper cell unit 146 and the lower cell unit 147, that is, the rated 36V is transferred from the battery pack 100 to the load device 70 of the power tool main body 1. will be output to .

FIG. 3(B) is a diagram showing the connection relationship between the terminal portion 50 of the power tool main body 1 having a rating of 36V and the connection terminals (162, 167, 172, 177) on the battery pack 100 side. The terminal section 50 is provided in the battery pack mounting section 2c of the power tool main body 1. The terminal section 50 is provided with device-side terminals (52, 59a, 54-56, 57, 59b, 58) corresponding to the slots 121-128 (see FIG. 2) of the battery pack 100, and has a base made of synthetic resin. It is fixed by being cast into 51. The upper connection terminal portion and the lower plate-shaped terminal portion of the base 51, which have the same reference numerals, are constructed of electrically conductive metal plates. Here, no device-side terminal is provided at the position corresponding to the slot 123 (see FIG. 2). As input terminals for power, a positive input terminal 52 for power reception and a negative input terminal 57 are small in size and are provided above the shorting terminals 59a and 59b. The positive input terminal 52 and the shorting terminal 59a are not electrically connected. Further, the negative input terminal 57 and the shorting terminal 59b are not electrically connected.

When the battery pack 100 is attached, the positive input terminal 52 is fitted only to the upper positive terminal 162, and the negative input terminal 57 is fitted only to the upper negative terminal 167. Further, the terminal portion 50 of the power tool main body 1 is provided with small terminals 59a and 59b that short-circuit the lower positive electrode terminal 172 and the lower negative electrode terminal 177. The small terminals 59a and 59b are for electrical connection (short circuit) using a short circuit 59, which will be described later.

The positive electrode input terminal 52 is a portion that fits into the upper negative electrode terminal 162 and connects the terminal portion formed in a flat plate shape to the circuit board side of the power tool main body 1 side. It is composed of a terminal portion that protrudes upward. The positive input terminal 52 is cast into a base 51 made of synthetic resin. The negative input terminal 57 is similar to the positive input terminal 52, and the height of the terminal portion 57 is slightly smaller than half that of the other terminal portions (54 to 56, 58). The other terminal portions (54 to 56, 58) are terminals for signal transmission. Recesses 51a and 51b are provided on the front and rear sides of the synthetic resin base 51 of the terminal portion 50 to be held between the housings.

In FIG. 3(B), when installing the battery pack 100, when the battery pack 100 is moved relative to the power tool main body 1 along the insertion direction, the positive input terminal 52 and the shorting terminal 59b are connected to the same terminal. It is inserted into the interior through the slot 122 (see FIG. 3) and is fitted into the upper positive electrode terminal 162 and the lower positive electrode terminal 172, respectively. At this time, the positive input terminal 52 is press-fitted between the arms 162a and 162b of the upper positive terminal 162 in such a way as to spread out the fitting part of the upper positive terminal 162, and the shorting terminal 59b is inserted into the lower positive terminal 172. The arm portions 172a and 172b are press-fitted so as to be pushed apart. Similarly, the negative input terminal 57 and the shorting terminal 59b are inserted into the same slot 127 (see FIG. 2) and fitted into the upper negative terminal 167 and the lower negative terminal 177, respectively. At this time, the negative electrode input terminal 57 is press-fitted between the arm portions 167a and 167b of the upper negative electrode terminal 167 so as to spread the space between the fitting portions. Further, the short-circuiting terminal 59b is press-fitted into the space between the arm portions 177a and 177b of the lower negative electrode terminal 177 so as to spread them apart. In this way, by realizing the connection form of FIG. 3(B), the output of the series connection of the upper cell unit 146 and the lower cell unit 147, that is, the rated voltage of 36V is output from the battery pack 100.

FIGS. 4A and 4B are diagrams showing the connection state when the battery pack 100 of this embodiment is attached to the conventional 18V power tool main body 201 (see FIG. 1). When the battery pack 100 is attached to the power tool main body 201, the terminal portion of the positive input terminal 222 is press-fitted so as to push open ends of the upper positive electrode terminal 162 and the lower positive electrode terminal 172 apart, and An upper part of the terminal portion of the positive input terminal 222 contacts the upper positive terminal 162 , and a lower part of the terminal part contacts the lower positive terminal 172 . In this way, by simultaneously fitting the terminal portion of the positive input terminal 222 into the arm portions 162a, 162b of the upper positive electrode terminal 162 and the arm portions 172a, 172b of the lower positive electrode terminal 172, the two positive electrode terminals (162 and 172) becomes short-circuited. Similarly, the terminal portion of the negative input terminal 227 is press-fitted so as to push open ends of both the upper negative terminal 167 and the lower negative terminal 177 apart, and the upper part of the terminal portion of the negative input terminal 227 The region contacts the upper negative electrode terminal 167 , and a part of the lower region contacts the lower negative electrode terminal 177 . In this way, by simultaneously fitting the terminal portion of the negative input terminal 227 into the arm portions 167a, 167b of the upper negative electrode terminal 167 and the arm portions 177a, 177b of the lower negative electrode terminal 177, the two negative electrode terminals (167 and 177) becomes short-circuited, and the output of the parallel connection of the upper cell unit 146 and the lower cell unit 147, that is, the rated voltage of 18V is output to the power tool main body 201.

As described above, when the battery pack 100 of this embodiment is attached to either the 18V power tool main body 201 or the 36V power tool main body 1, the output of the battery pack 100 is automatically switched. This voltage switching is not performed on the battery pack 100 side, but is performed automatically depending on the shape of the terminal portion on the power tool main body 1, 201 side, so there is no risk of voltage setting errors occurring. Further, since there is no need to provide a dedicated voltage switching mechanism such as a mechanical switch on the battery pack 100 side, a battery pack with a simple structure, low risk of failure, and long life can be realized.

When charging the battery pack 100 using an external charging device (not shown), it can be charged using the same charging device as a conventional 18V battery pack. The slot 121 of the battery pack 100 is provided with a charging positive terminal having the same shape as the upper positive terminal 162 and the lower positive terminal 172. The positive terminal (not shown) of the external charging device (not shown) may be connected to the positive terminal of the external charging device (not shown). In this way, the battery pack 100 is charged using an 18V charging device with the upper cell unit 146 and the lower cell unit 147 connected in parallel, so when charging the battery pack 100 of this embodiment, The advantage is that there is no need to prepare a new charging device.

FIG. 5 is a block diagram showing the internal circuit of the battery pack 100 of this embodiment. Here, only the basic components are illustrated to explain the connection status of the microcomputer 195 and the protection ICs 180 and 190 to the upper cell unit 146 and the lower cell unit 147, and other related circuits, especially the main body. Illustrations of circuits and the like for communicating with signal terminals on the device side are omitted. As shown in FIG. 4, the battery pack 100 includes an upper positive terminal (upper +) 162, a lower positive terminal (lower +) 172, an upper negative terminal (upper -) 167, and a lower negative terminal (lower). +) 177. In addition to these, the battery pack 100 is provided with other signal terminal groups (T terminal, V terminal, LS terminal, LD terminal), but illustration thereof is omitted here. The output of the upper cell unit 146 is connected to the upper positive terminal 162 and the lower negative terminal 177. That is, the positive electrode (+output) of the upper cell unit 146 is connected to the upper positive electrode terminal 162, and the negative electrode (−output) of the upper cell unit 146 is connected to the lower negative electrode terminal 177. Similarly, the positive electrode (+output) of the lower cell unit 147 is connected to the lower positive electrode terminal 172, and the negative electrode (−output) of the lower cell unit 147 is connected to the upper negative electrode terminal 167.

Protection ICs 180 and 190 for monitoring the voltage of the battery cells are connected to the upper cell unit 146 and the lower cell unit 147, respectively, and a microcomputer 195 is connected to these protection ICs 180 and 190. The protection IC 180 performs an overcharge protection function, an overdischarge protection function, a cell balance function, a cascade connection function, and a disconnection detection function by inputting the voltage across each battery cell of the upper cell unit 146. This is an integrated circuit commercially available as a "lithium ion battery protection IC." In addition, when the voltage of the battery cell of the upper cell unit 146 falls below a predetermined value and an overdischarge state occurs, the protection IC 180 outputs a signal (high signal) 183 indicating overdischarge to the microcomputer 195, and If the voltage of the battery cell of the cell unit 146 reaches a predetermined value or higher during charging and an overcharge state occurs, a signal (high signal) 184 indicating overcharge is output to the microcomputer 195.

A protection IC 190 is connected to the lower cell unit 147. Here, a microcomputer 195 is further provided in the circuit of the lower cell unit 147, that is, in the circuit between the lower positive electrode terminal 172 and the upper negative electrode terminal 167. In other words, the protection circuit provided in parallel with the upper cell unit 146 is composed of only the protection IC 180, whereas the protection circuit provided in parallel with the lower cell unit 147 is composed of the protection IC 190 and the microcontroller unit (Micro Controller Unit) 195. including. The output from the protection IC 180 (over-discharge signal 183, over-charge signal 184) and the output from the protection IC 190 (over-discharge signal 191, over-charge signal 192) are input to the microcomputer 195. The microcomputer 195 includes, for example, a voltage detection circuit called an analog front end (AFE), and measures the value of the current flowing to the lower cell unit 147 from the output voltage of the current detection circuit 193. Power for driving the microcomputer 195 is generated by a power supply circuit 185 connected to the lower cell unit 147, and the power supply (VDD1) is supplied to the microcomputer 195. A shunt resistor 194 is provided on the ground side of the lower cell unit 147 to measure the current value.

The microcomputer 195 monitors the current value and cell temperature, as well as the states of the upper cell unit 146 and the lower cell unit 147, and integrates and controls the operating states of both. Furthermore, when it becomes necessary to urgently stop the power tool main body 1, a discharge prohibition signal is sent to the electrical equipment main body via an LD terminal (not shown). The protection IC 190 monitors the voltage of the battery cells in the lower cell unit 147, and sends an overdischarge signal 191 to the microcomputer 195 when a state in which the voltage has decreased to a predetermined lower limit value (an overdischarge state) is detected. Further, when the battery pack 100 is attached to an external charging device (not shown) and being charged, the protection IC 190 detects overcharging if it detects that the voltage of the battery cell exceeds a predetermined upper limit value. An overcharge signal 192 indicating the state is sent to the microcomputer 195. The microcomputer 195 sends a charging stop signal to a charging device (not shown) via an LS terminal (not shown).

The power supply circuit 185 generates power for operating the microcomputer 195 using the power of the lower cell unit 147. Since the battery pack 100 of this embodiment is a voltage switching type between 18V and 36V, if a microcomputer is installed in the protection circuit on the upper cell unit 146 side, the ground of the microcomputer 195 will be affected when the two cell units are connected in series or in parallel. The potential changes. On the other hand, if the power supply circuit 185 is provided on the lower stage side, the ground potential of the power supply circuit 185 does not change. Therefore, in this embodiment, the microcomputer 195 is provided not in the circuit of the upper cell unit 146 but in the circuit of the lower cell unit 147. This arrangement of the microcomputer 195 allows the microcomputer 195 to operate stably even when the output voltage is switched between the rated 18V and 36V. The microcomputer 195 can switch between holding and releasing the power supply voltage (VDD1) applied to itself, and has a normal operating state (normal mode) and an operating stopped state (so-called sleep mode).

The output of the upper voltage detection circuit 182 connected to the upper positive terminal 162 is input to the microcomputer 195 . This output indicates the potential of the upper cell unit 146 when the battery pack 100 is not attached to the power tool main body 1, 201 or an external charging device (not shown). On the other hand, when attached to the power tool body 1 for low voltage (18V), the upper positive electrode terminal 162 and the lower positive electrode terminal 172 are connected, so the positive electrodes of the upper cell unit 146 and the lower cell unit 147 are connected. They have the same potential, and each negative electrode has the same potential. From this, the microcomputer 195 compares the potential of the upper positive terminal 162 with the potential of the lower positive terminal 172 to determine whether the battery pack 100 is not attached or attached to the main body of the low-voltage device. It can be determined whether it is attached to high voltage equipment. In order to detect the potential of the lower positive electrode terminal 172, it is preferable to configure the microcomputer 195 so that it can acquire the positive electrode potential of the uppermost battery cell 147a among the battery cells in the lower cell unit 147. Although not shown in FIG. 5, there are situations in which the power supply from the battery pack 100 must be stopped, such as excessive current during discharge, decrease in cell voltage during discharge (overdischarge), and abnormal rise in cell temperature (overdischarge). temperature) etc., the operation of the power tool main bodies 1 and 201 can be quickly stopped by transmitting the LD signal to the power tool main body side via the microcomputer 195.

FIG. 6 is a circuit diagram of the power tool main body (high voltage electrical equipment) 1 to which the battery pack 100 is attached, and has a basic circuit configuration in which a switch is not used in the short circuit (short circuit path) 59. The right side is the battery pack 100, and the specific circuit configuration is as shown in FIG. 5, but only the necessary configuration is extracted and illustrated here for ease of explanation. To extract the voltage of 36V from the battery pack 100 to the power tool main body 1 having a rating of 36V, a short circuit 59 shown by a thick line is provided in the terminal portion 50A on the power tool main body 1 side. The short circuit 59 can be configured with a short circuit made of a metal plate, and as shown in FIG. It can be constructed by casting a metal plate bent into a shape. One end of the metal plate bent into a U-shape becomes a short-circuit terminal 59a, and the other end becomes a short-circuit terminal 59b. By simply attaching the battery pack 100 to the terminal portion 50A having such a shape, 36V rated DC power is supplied to the positive input terminal 52 and the negative input terminal 57. The power tool main body 1 includes a microcomputer 60 for controlling the rotation of the motor 3. A voltage (5 V or 3.3 V) for driving the microcomputer 60 is supplied by a power supply device 61 that receives the voltage across the shorting terminal 59a and the negative input terminal 57 as input. By providing the terminal section 50A having the short circuit 59 in the power tool main body 1 in this manner, the battery pack 100 of this embodiment having two positive terminals (162, 172) and two negative terminals (167, 177) can be used. A series connection circuit between the upper cell unit 146 and the lower cell unit 147 can be established just by attaching it.

FIG. 7 is a circuit diagram of the high voltage electrical device (power tool main body 1) according to this embodiment. Although the basic circuit configuration is the same as that shown in FIG. 6, the wiring of the terminal section 50 has been changed in order to interpose a main switch 63 in the middle of the short circuit 59, which can control on/off connection from a microcomputer 60. The main switch 63 is in a disconnected state (off state) when an on signal from the microcomputer 60 is not output. The reason why the main switch 63 is provided is not to short-circuit the short-circuiting terminals 59a and 59b immediately after the battery pack 100 is attached to the battery pack attachment part 2c of the power tool main body 1, but to ensure that each terminal part is properly connected. This is because the microcomputer 60 checks whether an abnormal short-circuit condition has occurred, and connects the main switch 63 (turns it on) after confirming that the connection is normal. That is, the main switch 63 is configured not to turn on immediately after the battery pack 100 is attached, but to turn on with a delay. During this delayed turn-on time, the microcomputer 60 detects short circuits and poor contacts between the positive terminal group (52, 59a, 162, 172) and the negative terminal group (57, 59b, 167, 177). Detect whether there is any. When the microcomputer 60 detects a connection abnormality in each terminal portion, it maintains the disconnected state (off state) without turning the main switch 63 into the on state. Therefore, when an abnormality occurs in the connection terminal portion, power for operation will not be supplied from the battery pack 100 to the load device 70 of the power tool main body 1. Therefore, the risk of damage to the equipment due to short circuit between the terminals can be almost eliminated.

The microcomputer 60 is operated by a low-voltage DC power supply 61 for driving supplied from a power supply 61 . The power supply device 61 receives power from the shorting terminal 59a and the negative input terminal 57. Therefore, regardless of whether the main switch 63 is on or off, the terminal section 50 and the battery pack 100 are attached, and the shorting terminal 59a and the lower positive terminal 172, and the negative input terminal 57 and the upper negative terminal 167 are connected. If the connection is normal, power is supplied to the power supply device 61, so the microcomputer 60 operates normally.

The microcomputer 60 includes, for example, a voltage detection circuit called an analog front end (AFE), and the input port of the microcomputer 60 receives a voltage (V3) from the positive input terminal 52 and a voltage (V2) from the short-circuit terminal (59a). ), the voltage (V1) from the shorting terminal (59b), and the power (V0) from the negative input terminal 57, the microcomputer 60 can measure the potential of the voltages V0 to V4. An output port (A/D output terminal) of the microcomputer 60 is connected to a second switch 68 and a third switch 65. In addition, the microcomputer 60 inputs and outputs various signals such as various control signals, input signals from sensors, output control signals to a lighting device 71 such as an LED, and control signals to the battery pack 100. . The second switch 68 is a switch that can be switched between an off state and an on state under the control of the microcomputer 60, and connects the shorting terminal 59a and the shorting terminal 59b via a resistor R1. The resistor R1 has a sufficiently large resistance value so that even if a short circuit occurs on the positive terminal side (52 and 59a) or the negative terminal side (57 and 59b), only a small current flows through the second switch 68. do. The second switch 68 is in a connected state (on state) when there is an on signal from the microcomputer 60, and becomes a cutoff state (off state) when the on signal from the microcomputer 60 disappears. Here, the second switch 68 and the resistor R1 constitute a bypass connection circuit used when measuring the voltage of the microcomputer 60.

The third switch 65 is a switch circuit provided to turn on the main switch 63. Originally, if the microcomputer 60 could directly control the on/off of the main switch 63, there would be no need to intervene with the third switch 65. However, since the operating voltage on the microcomputer 60 side is as low as 5V or 3.3V, the high-power semiconductor switching element M1 (described later in FIG. 8) used as the main switch 63 can be operated stably with just a high signal from the microcomputer 60. It's difficult to make it happen. Therefore, the microcomputer 60 controls the on/off of the third switch 65 to extract the divided voltage of the resistors R2 and R3 (described later in FIG. 8) between the positive input terminal 52 and the shorting terminal 59b. The voltage was supplied to the main switch 63. With this configuration, the main switch 63 can be stably kept in the on state while the load device 70 of the power tool main body 1 is operating.

FIG. 8 is a detailed circuit diagram of the main switch 63, second switch 68, and third switch 65 shown in FIG. The main switch 63 is constituted by a semiconductor switching element M1 using an FET (field effect transistor). The second switch 68 is constituted by a semiconductor switching element M2 using an FET (field effect transistor). Note that the second switch 68 may be configured not only by the semiconductor switching element M2 but also by a relay or a photocoupler. If a photocoupler is used, it may be configured in the same manner as the third switch 65 described later. The third switch 65 includes a photocoupler 66, resistors R2 and R3 for voltage division, and a resistor R4 for adjusting the current of the light emitting diode 66a included in the photocoupler 66. One side (negative side) of the power circuit to the light emitting diode 66a is connected to the shorting terminal 59a, and the other side is connected to the output port (A/D output terminal) of the microcomputer 60. Therefore, when the microcomputer 60 changes from a high impedance state to a low state, the light emitting diode 66a emits light, and the light makes the output side phototransistor 66b conductive. The collector side of the phototransistor 66b is connected to the positive input terminal 52 side, and the negative side is connected to the shorting terminal 59b via two resistors R2 and R3. A midpoint between resistor R2 and resistor R3 is connected to the gate of semiconductor switching element M1. Since there is a sufficient potential difference of 18V between the positive input terminal 52 and the shorting terminal 59b, it is possible to stably keep the semiconductor switching element M1 in the on state by the divided voltage of the resistor R2 and the resistor R3. .

FIG. 9 is a flowchart showing a connection control procedure when the battery pack 100 is attached to the high-voltage electric device (power tool body 1) according to this embodiment. The series of controls shown in FIG. 9, except for step 98, can be executed by software using a program stored in the microcomputer 60 in advance. First, when the battery pack 100 is attached to the power tool main body 1, DC power for operation is supplied from the power supply device 61 to the microcomputer 60, so the microcomputer 60 starts up, and a series of processes shown in FIG. 9 are executed. . Further, even if the battery pack 100 is attached to the power tool main body 1, if the microcomputer 60 that has been shut down is activated by the activation signal, the series of controls shown in FIG. 9 is started.

Immediately before executing the control shown in the flowchart shown in FIG. 9, the main switch 63, second switch 68, and third switch 65 shown in FIG. 7 are each in an off state. First, the microcomputer 60 turns on only the second switch 68 to connect the shorting terminals 59a and 59b using a bypass connection circuit with a resistor R1. This connection is made by inputting the output (on signal) from the microcomputer 60 to the second switch 68. When the second switch 68 uses the same photocoupler as the third switch 65, the microcomputer 60 changes the port connected to the cathode of the diode from a high impedance state to a low state. When the second switch 68 is turned on, the connection between V1 and V2 becomes conductive (on state). By turning on the second switch 68, the voltage (36 V) of the series connection of the upper cell unit 146 and the lower cell unit 147 of the battery pack 100 is applied to the positive input terminal 52 and the negative input terminal 57. When this series connection path with high resistance (R1) is established, the microcomputer 60 measures the voltages of V1, V2, and V3, respectively, with the terminal voltage V0 as a reference.

Next, the microcomputer 60 determines whether the measured voltages V1 and V0 are the same from each measured voltage value (step 92). In a high-voltage electric device, when the negative input terminal 57 is set to the ground potential, the voltage (V1) of the shorting terminal 59b is supposed to be +18V (rated). It is normal if the measured voltages V1 and V0 are different, and if normal, proceed to step 93. If the measured voltages V1 and V0 are the same, the connection path between the shorting terminal 59b and the lower negative terminal 177 (originally +18V) and the connection path between the negative input terminal 57 and the upper negative terminal 167 (originally ground potential) This means that a short circuit has occurred between the connection paths, so the process advances to step 96 to perform processing when a short circuit occurs.

In step 93, the microcomputer 60 determines whether the measured voltages V2 and V3 are the same. In a high-voltage electrical device, the positive input terminal 52 is supposed to be +36V (rated), and the short-circuit terminal 59a is supposed to be +18V (rated). Therefore, it is normal if the measured voltages V2 and V3 are different, and if normal, the process proceeds to step 94. If the measured voltages V2 and V3 are the same, the connection path between the shorting terminal 59a and the lower positive electrode terminal 172 (originally +18V) and the connection path between the positive input terminal 52 and the upper positive electrode terminal 162 (originally +36V). This means that a short circuit has occurred between the connection paths, so the process advances to step 96 to perform processing when a short circuit occurs.

In step 96, the microcomputer 60 immediately turns off the second switch 68 to cut off the bypass connection circuit with the resistor R1. When the second switch 68 is in the OFF state, there is no connection between the short-circuiting terminals 59a and 59b, so even if a short-circuit phenomenon occurs on the positive input terminal 52 side and the negative input terminal 57 side, Since the connection is the same as the connection for low-voltage electrical equipment shown in FIG. 4, damage to the battery pack 100 and the power tool main body 1 can be avoided. In addition, since each terminal on the positive side (52, 59a, 162, 172) and each terminal on the negative side (57, 59b, 167, 177) are arranged physically apart, foreign objects and terminal parts can be avoided. There is almost no possibility that the positive terminal and the negative terminal will be short-circuited due to deformation or the like. In addition, since the power supply for the operation of the microcomputer 60 is obtained from the voltage (172, 167) across the lower cell unit 147 as shown in FIG. The microcomputer 60 operates as long as the terminal 59b and the lower negative terminal 177 are connected.

Next, the microcomputer 60 issues an alarm to the operator that an abnormality has occurred in the connection state of the battery pack 100 (step 97). There are various ways to issue an alarm, but it is preferable to use light or sound. For example, all the lights of the illumination device 71, such as the LED for displaying the remaining battery power and the LED for setting the striking strength, may be made to blink at rapid intervals. When the operator receives the alarm output, the power to the microcomputer 60 is stopped by removing the battery pack 100 from the power tool main body 1, so that the control shown in FIG. 9 is forcibly terminated.

In steps 92 and 93, if V0≠V1 and V2≠V3, the microcomputer 60 outputs a low signal to the third switch 65 (changes it from a high impedance state to a low state), so that the light emitting diode of the photocoupler 66 66a is made conductive. By making the phototransistor 66b on the output side of the photocoupler 66 conductive, the potential difference between the shorting terminal 59b and the positive input terminal 52 is used to divide the voltage between the resistors R2 and R3. Take out the voltage. The divided voltage of the resistors R2 and R3 is provided to take out the gate signal of the semiconductor switching element M1 of the main switch 63, and since the semiconductor switching element M1 is turned on by this divided voltage, the shorting terminals 59a and 59b are connected. A short circuit is established between the two and a power path is established for the 36V connection. As a result, 36V rated DC is supplied to the load device 70 (step 95). The power supply path in step 95 is the same as the connection path of the conventional impact tool 201, and this power supply path continues until the microcomputer 60 is shut down or the battery pack 100 is removed.

In the control shown in the flowchart of FIG. 9, the control focused only on the occurrence of short circuits in the positive terminal group and the negative terminal group. However, in addition to detecting the occurrence of a short circuit, when detecting a unique potential that differs from the normal state, for example, when V1 should be around 18V, but it is only about 9V, the voltage value The microcomputer 60 may also detect abnormalities and poor contact. Even when such an abnormality is detected, the microcomputer 60 may output an alarm.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments, and various changes can be made without departing from the spirit thereof. For example, in the above embodiment, the battery pack 100 is switchable between 18V and 36V, but the combination of voltages that can be switched is not limited to 18V/36V, and can be switched by a combination of series connection and parallel connection. It may be a voltage group. Further, in the above-described embodiment, the second switch 68 constituting the bypass connection circuit that connects the short-circuiting terminals 59a and 59b is controlled to be turned off when the main switch 63 is turned on. There is no problem even if the second switch 68 is kept in the on state together with the second switch 63. Therefore, the second switch 68 is controlled in conjunction with the startup or shutdown of the microcomputer 60, and when the microcomputer 60 is started, the second switch 68 is turned on, and when the microcomputer 60 is stopped (shutdown or sleep), the second switch 68 is turned off. It is also possible to configure such a configuration. Furthermore, as another configuration, another delay connection means is provided in place of the main switch in the short circuit having the main switch, so that when the battery pack 100 is attached to the power tool main body 1, a predetermined time, e.g. The configuration is such that the short circuit is connected after a delay time of about seconds, and during this delay time the microcontroller measures the voltage at each terminal to detect an abnormality such as a short circuit, and if an abnormal condition occurs, the main switch It may be configured to prevent the switch from turning on.

1 Power tool body 2 Housing 2a Body part 2b Handle part 2c Battery pack attachment part 3 Motor 4 Operation switch 5 Forward/reverse switching lever 8 Attachment mechanism 10 Output shaft 11 Power tool body 20 Terminal part 22 Positive input terminal 22a Terminal part 27 Negative input Terminal 27a Terminal section 50, 50A Terminal 51 Base 51a, 51b Recess 52 Positive input terminal 52 Terminal section 52c Wiring section 54c Wiring section 57 Negative input terminal 57 Terminal section 59 Short circuit 59a, 59b Short circuit terminal 60 Microcomputer 61 Power supply device 63 Main switch 65 Third switch 66 Photocoupler 66a Light emitting diode 66b Phototransistor 68 Second switch 70 Load device 71 Lighting device 100 Battery pack 101 Lower case 110 Upper case 111 Lower surface 115 Upper surface 121 to 128 Slot 131 Stopper portion 132 Protrusion 138a, 138b Rail 141 Latch 142 Locking part 146 Upper cell unit (first cell unit)
147 Lower cell unit (second cell unit)
147a Battery cell 150 Circuit board 162 Upper positive terminal (first positive terminal) 162a, 162b Arm 167 Upper negative terminal (second negative terminal) 167a, 167b Arm 172 Lower positive terminal (second positive terminal) 172a, 172b Arm portion 177 Lower negative electrode terminal (first negative electrode terminal) 177a, 177b Arm portion 180 Protection IC 182 Upper voltage detection circuit 183 Overdischarge signal 184 Overcharge signal 185 Power supply circuit 190 Protection IC
191 Over-discharge signal 192 Over-charge signal 193 Current detection circuit 194 Shunt resistor 195 Microcomputer 201 Impact tool 202 Housing 202a Body part 202b Handle part 202c Battery pack mounting part 204 Operation switch 205 Forward/reverse switching lever 208 Mounting mechanism 210 Output shaft 220 Terminal part 222 Positive input terminal 227 Negative input terminal M1, M2 Semiconductor switching element R1 to R4 Resistor

Claims (9)

An electrical device body to which a battery pack can be attached,
A battery pack mounting part to which the battery pack can be mounted, the battery pack mounting part having a positive input terminal, a negative input terminal, a first short-circuit terminal, and a second short-circuit terminal connectable to the battery pack. and,
A short-circuit circuit having a conductive state in which the first short-circuit terminal and the second short-circuit terminal are connected to each other, and a disconnected state in which the first short-circuit terminal and the second short-circuit terminal are mutually disconnected. and,
a load device configured to receive power from the battery pack via the negative input terminal, the first shorting terminal, the shorting circuit, the second shorting terminal, and the positive input terminal;
Equipped with
When the positive input terminal and the first short-circuit terminal are short-circuited, or when the negative input terminal and the second short-circuit terminal are short-circuited, the short circuit enters the disconnected state and the battery pack is disconnected. configured to cut off power supply to the load device;
An electrical equipment main body characterized by: The electrical equipment main body according to claim 1,
When the battery pack is attached to the battery pack mounting portion with the positive input terminal and the first shorting terminal short-circuited, or with the negative input terminal and the second shorting terminal short-circuited, , the short circuit is cut off,
An electrical equipment main body characterized by: The electrical equipment main body according to claim 1,
The battery pack mounting portion has a pair of rail grooves configured to extend in a mounting direction in which the battery pack is mounted and to be spaced apart in a left-right direction intersecting the mounting direction,
The positive input terminal, the first shorting terminal, the second shorting terminal, and the negative input terminal are arranged inside the pair of rail grooves in the left-right direction,
An electrical equipment main body characterized by: The electrical equipment main body according to claim 1,
having a cutting part for bringing the short circuit into the disconnected state;
An electrical equipment main body characterized by: The electrical equipment main body according to claim 4,
a microcomputer that detects voltages of each of the positive input terminal, the first short-circuit terminal, the second short-circuit terminal, and the negative input terminal;
The cutting section is configured to be turned on and off by the microcomputer,
An electrical equipment main body characterized by: The electrical equipment main body according to claim 1,
The first shorting terminal is configured to be connectable to the positive electrode of one of the plurality of cell units constituting the battery pack,
The second shorting terminal is configured to be connectable to the negative electrode of another cell unit among the plurality of cell units,
The short circuit is configured to connect the plurality of cell units in series,
An electrical equipment main body characterized by: The electrical equipment main body according to any one of claims 1 to 6,
a battery pack that can be attached to the battery pack attachment part;
Equipped with
An electrical device characterized by: The electrical device according to claim 7,
The battery pack includes:
A plurality of cell units in which a plurality of battery cells are connected in series,
a second positive electrode terminal connected to the positive electrode of one of the plurality of cell units;
a second negative electrode terminal connected to the negative electrode of the first cell unit;
a first positive electrode terminal connected to the positive electrode of another cell unit among the plurality of cell units;
a first negative electrode terminal connected to the negative electrode of the another cell unit;
a case that accommodates the plurality of cell units, the second positive terminal, the second negative terminal, the first positive terminal, and the first negative terminal;
has
The first shorting terminal is configured to be connectable to the second positive terminal,
The second shorting terminal is configured to be connectable to the first negative terminal.
An electrical device characterized by: The electrical device according to claim 8,
The short circuit is configured to connect the plurality of cell units in series,
An electrical device characterized by:

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